//侧边栏
function switch_sidebar() {
    let sidebar = document.getElementById("sidebar");
    let swbtn = document.getElementById("swbutton").childNodes[0];
    if (sidebar.style.display != "none") {
        sidebar.style.display = "none";
        swbtn.innerHTML = '>';
    } else {
        sidebar.style.display = "inline";
        swbtn.innerHTML = '<';
    }
}
